Spinneret



` July 24, 1934.

j j 5 z K. WITTE SPINNERET Filled June 4, 1950 Eiqll gmc/whom fiar? We,

Patented July 24, 1934 UNET STATES SPINNERET Kurt Witte, St. Polten, Austria, assignor to North American Rayon Corporation, New York, N. Y.

Application June 4, 1930, Serial No. 459,235 In Germany June 4, 1929 1 Claim.

The present invention refers to a spinneret for the manufacture of rayon, particularly viscose rayon, and has special reference to all those Working methods wherein acid containing spin- 5 ning baths, especially those containing sulphuric acid., were used. The spinneret consists of a precious metal, i. e. a metal which is not corroded by acids and alkali, such as gold, platinum or alloys of these metals, such as gold-platinum i0 alloy, gold-palladium alloy, etc. The spinneret may have the usual form of a cup and be pressed out in the usual manner from a thin metal sheet,

for example, one the thickness of 0.3 or 0.5 mm.

Instead of the usual spinning holes the spin- 3,5 neret is set with small stones in the form of precious stones or suitable semi-precious stones such as rubies, Sapphires, garnets, so-called watch-jewels, or similar substances made from hard, natural or artificial glass, which are drilled with minute holes, for example holes 0.12 mm. in diameter. These small stones are set into the spinneret in such a manner that the stones form a perfectly even surface on the outside of the spinneret i. e. in such a manner as to avoid any unevenness, projections and edges on the outer surface of the spinneret.

A spinneret provided with an arrangement as described in this invention is shown as an example in the enclosed drawing.

Figure 1 is a plan View, partly in cross section, showing one form of the improved spinneret.

Figure 2 is an enlarged View of a portion of the bottom plate of the spinneret head showing the manner in which the precious stones are set therein.

Figure 1 shows four inlaid stones 1 afxed in the spinneret bottom plate 2. In aflixing these stones, small holes 3, are drilled at the desired positions through the plate 2. A further cylindrical drilling from the outside, 4, is then made. The stone 1, provided with the drilled hole 5, is then set into the enlarged cylindrical opening Ll, after which the projection 6 is pressed over to grip the edges of the stone. This portion 6 serves to irmly hold the stones in place. The bottom surface is then polished to smoothness in any desired manner.

A further advantage arises from the fact that the stones may be set into the spinneret head using metal of usual thickness. By any other method of stone setting, a thicker plate would be necessary.

I claim:

A spimieret for use in the manufacture of artiiicial filaments, comprising a metallic member of acid-resisting material, holes extending therethrough, the outer ends of the holes being enlarged to form a shoulder Within the member, a drilled stone fitted snugly within the enlarged portion of the hole and against the shoulder, the outer edge of said stone being bevelled, and the metal of said member adjacent the stone being pressed against the bevelled portion of the stone to grip the edge of the same, the outer surfaces of the stone, and of the member proper forming a substantially perfectly even surface on the outside of the spinneret.

KURT WITTE. 

